TeddFoxx

I've got a 91 f150 5.0 that won't start. It's been running rough the past few days but today it stopped running.

Currently the engine turns over but it doesn't start.

The most abnormal thing i have noticed over the past few days is that the fuel pump sound when the key is turned to the on position, no matter which tank is selected, does not sound like it normally does...sounds as if it were not getting enough voltage.

I have not checked fuel pressure at this time. I checked codes the other day, and the only noticeable thing was a sensor issue, i believe it was this:

137

(R)

Oxygen sensor not switching/system rich Left or Front HO2S – Fuel control

i can't remember as i don't have what i wrote down in front of me.

All my gauges seem fine, with the KOEO the battery gauge does read low but goes up if the engine does start to run...

i've also noticed that the idle this morning was lower than what i'm used to out of this truck....it usually is just below a 1000, and this morning was just above 500...

Any thoughts suggestions are appreciated. I was thinking the battery might be going out and wasn't supplying enough power to the pumps, but the starter seems to be working normally..

thats all i got. I know i need to check fuel pressure.

memoniz

This is just a thought.Look at your negative battery cable. They seem to corrode easily and can cause all sorts of weird issues. And when I say corrode, I mean it does it under the sleeve, down the wire some. You may want to replace it.

TeddFoxx

Ended up being the fuel pressure regulator went bad. Fuel came out of the vac line, so fuel was flooding the engine. Replaced the regulator, spark plugs, and changed the oil. She’s back to life.

Chris_1

iTrader: (1)

That'd do it.
That happens a lot with old regulators. You'd think they could have designed them to last longer than 25 years !
lol